Shutter mechanism



J1me L. B. HQFFMANN SHUTTER MECHANISM Filed May 19, 1941 8 Sheets-Sheetl June 6, 1944. HQFFMANN 2359 355 SHUTTER MECHANISM Filed May 19,- 19418 Sheets-Sheet 3 June 6, 1944. L. B. HOFFMANN SHUTTER MECHANISM FiledMay 19, 1941 8 Sheets-Sheet 4 a. J ml .HHHMHHHMWHNW Tm l .n i

June 6, 1944. L. a. HOFFMANN 2,350,355

SHUTTER MECHANISM Filed May 19, 1941 8 Sheets-Sheet s 20 fly a 1.. B.HOFFMANN 2,350,355 SHUTTER MECHANISM Filed May 19 1941 8 Sheets-Sheet 6f 1' mayday/ III-LI VIIIIIIIIIIIIIIIIIIIWilli/I100 In 273 June 6, 1944.L. B. HOFFMANN 2,350,355

SHUTTER MECHANISM Filed May 19, 1941 8 Sheets-Sheet 7 June 6, 1944. L B.HOFFMANN SHUTTER MECHANISM Filed May 19, 1941 Patented June 6, 1944SHUTTER MECHANISM Louis B. Hoffmann, Los Angeles, Calif., assignor toMitchell Camera Corporation, West Hollywood, Calif., a corporation ofDelaware Application May 19, 1941, Serial No. 394,122

46 Claims.

This invention relates generally to camera shutters, particularly andillustratively to rotary type shutters for cameras designed to takesuccessive still photographs from aircraft, though not necessarilylimited to cameras of that class.

Shutters of the type in question must be designed both for largeaperture and short exposure time, and for high exposure efliciency. Forexample, very large iris opening may be desired, while the exposuretimes may range from ,5 sec. to /3 0 sec. or less. It is thereforeevident that the shutters must be of relatively large size, and must beaccelerated in short times to relatively high velocities andsubsequently decelerated to rest. This combination of designrequirements presents certain evident problems For example, it has beencommon practice to drive shutters by means of a spring, which may bemade to accelerate the shutters to the necessary extent providedsufficient acceleration time and travel are available. However, theproblem of stopping the shutters has remained unsolved in a fullysatisfactory manner. efforts to arrest the motion of the shutters beforethey can give a second exposure being made extremely difficult by thevery high momentum which they acquired. Also the mere mechanical problemof providing shutter structure and power transmission light enough to bereadily accelerated and strong enough to take the accelerating forceswithout distortion, has been found to be a problem of some magnitude inshutters of large aperture. This applies to both positive and negativeacceleration.

A general object of my invention is to provide a shutter and drivingmechanism which may be used for large apertures as well as small, whichwill attain high speeds and high exposure efficiency, and in which thenecessary accelerating and decelerating forces are small and themechanism is subjected to correspondingly small forces and stresses.

Other and more detailed objects will appear from the followingdescriptions of the corresponding accomplishments and the preferredmechanisms, their functions and design. A preliminary description of thecharacteristic features of the present preferred form of the inventionwill enable it to be understood more readily.

The driving mechanism of the invention includes, as one of its majorcharacteristics, a closed system or train which, when in what may betermed its normal condition, is movable as a whole without relativedisplacement between its parts.

This closed train includes, as one of its elements, an energy storingunit, e. g. a spring. The movable shutter unit is drivingly connected toone end, the energy output end, of the distortable storing unit.

In the normally closed train, directly connected to the driving end ofthe energy storing unit and to the shutter unit, there is an elementwhich may be acted upon to arrest movement. This element, formed andacting to be capable of arresting the movement preferably at variousselected positions, is here termed the selector.

Between the selector and the energy receiving end of the distortablestoring unit there is a lost motion mechanism in the closed train,consisting typically of two engageable abutments which are separable insuch direction that the abutment connected to the energy receiving endof the storage unit may move away from the abutment connected to theselector and the energy output end in the direction of movement of thesystem as a whole.

In such a system, when movement energy is applied at any point to theclosed train either from an external source or from an acquired momentumof the train or shutter unit, and when the selector is not stopped, thecomplete mechanism will move freely as a wholeit will free wheel" orcoast. If the selector be stopped and energy then applied to any pointin that part of the train connected directly with the energy receivingend of the storage unit (e. g. the winding end of a spring) then thatend of the storage unit will move ahead while the selector and shutterunit stand still. The amount by which the storage unit will be stressedin receiving energy, depends then on how far its receiving end is movedafter its delivery end is stopped; and that may be determined andadjusted either by providin an adjustably variable point at which thedeliver end is stopped, or an adjustably variable point at which thestressing of the storage unit is stopped. The former is preferred, andthus the selector is placed in that position in the train which has beenstated, and the stressing of the storage unit is terminated by a fixedposition stop.

After the storage unit has been stressed and its energy receiving endprevented from backing up by suitable means, then if the energy deliveryend he released (as by releasing the selector) the stored energy willdrive th previously held part of the train and the shutter unit forwaruntil they reach a position corresponding to that to which the otherpart of the train was previously advanced. The speed to which theshutter unit is accelerated depends on the amount of energy which hasbeen selectively stored in the storage unit. At the end of shutterdriving movement the stop which limited the supply of energy to thestorage element is removed, the two separable abutments re-engage, andthe whole system is then again in condition for free wheeling orcoasting until its momentum is dissipated or absorbed and it comes to astop. The whole mechanism can thus be decelerated from very highvelocities with minimum accompanying stresses.

The necessary stresses involved in initial acceleration while the energystorage is driving the shutter unit depend among other things on theacceleration time period. The preferred type of shutter unit is onewhich allows a relatively long shutter movement before the shutterreaches its exposure position. Consequently, as will be seen, thenecessary accelerating forces and accompanying stresses on the mechanismare kept low.

In the present specific preferred form, the shutter unit comprises ahigh speed rotary shutter, a low speed rotary shutter, and anoscillatory auxiliary shutter. The high speed shutter, rotating at sayeight times the speed of the low speed shutter, produces eight shutteropenings at the exposure axis for one shutter opening provided by thelow speed shutter. Each eighth high speed shutter opening at theexposure axis coincides with a low speed shutter opening at said axis,so that an exposure may result. The advantage in using this combinationof low and high speed shutters is that the high speed shutter mayaccelerate through a number of revolutions without producing anexposure, and when finally up to speed, the low speed shutter then opensand an exposure results, the duration of which is governed, among otherthings, by the speed attained by the high speed shutter. Incidently,this speed may reach six or seven thousand revolutions or more perminute, depending upon the drive spring used. The auxiliary shutternormally stands across the exposure axis, and is preferably drawn asidejust before the high and low speed shutters are started to rotate. It isthen caused to move back in line with the exposure axis after thecoincidence of the high and low speed shutter openings at said axis, andbefore the occurrence of the next low speed shutter opening at the axis.Thus the high and low speed shutters may be permitted to coast to astop, since even though there will be a coincidence of high speed andlow speed shutter openings at the exposure axis each eighth revolutionof the high speed shutter, the auxiliary shutter moves into occultingposition after the first coincidence, and subsequent coincidencestherefore do not produce further exposures. It will be evident that ifthe shutters are braked to a stop before the low speed shutter makes acomplete revolution following exposure. the auxiliary shutter may bedispensed with. and in simple forms of my invention, for some purposes,the auxiliary shutter may thus be eliminated.

In addition to what has been outlined, the invention further providesvarious automatic actuations and controls which will be best understoodboth in their broad functional characteristics and in their specificallypreferred designs from the following detailed descriptions. And variousobjects and accomplishments not named above will be gathered from thefollowing detailed description of one present illustrative embodiment,reference being had to the accompanying drawings, in which:

Fig. 1 is a top plan view, partially broken away,

of a shutter mechanism in accordance with the invention;

Fig. 2 is a detail taken in accordance with arrows 2--2 on Fig, 1;

Fig. 3 is a vertical section, the upper portion being taken on line 3-3of Fig. 1 and the lower portion being taken on line 3a-3a of Fig. 4;

A Fig. 4 is a horizontal section taken on line 4-4 of Fig. 3 and Fig.17; r

Fig. 4a is an enlarged detail section on line la-la of Fig. 4;

Fig. 5 is a horizontal section taken on line 55 of Fig. 3;

Fig. 6 is a vertical section taken on line 6-6 of Fig. 1;

Fig. 7 is a section taken on broken line 1-1 of Fig.6;

Fig. 8 is a section taken on broken line 8-8 of Fig. 6;

Fig. 9 is a section taken on broken line 9-9 of Fig. 6, but omitting forclarity certain parts below which are shown in Fig. 10;

Fig. 10 is a section taken on line iii-i0 of Fig. 6, but omitting forclarity certain parts below which are shown in Fig. 11;

Fig. 11 is a section taken on line ||--ll of Fig. 6;

Fig. 12 is a section taken on line i2l2 of Fig. 6;

Fig. 13 is a section taken on line |3-l3 of Fig. 6;

Fig. 14 is a view similar to Fig. 13, but showing another position andwith parts broken away to the section line "-14 on Fig. 6;

Fig. 15 is a section taken on line i5--l5 of Fig.

Fig. 16 is a section, with parts broken away, taken on line Iii-l6 ofFigs. 3, 6 and 17;

Fig. 160. is an enlarged detail section on line |6al6a of Fig. 17;

Fig. 17 is a section taken on line il-ll of Fig. 1;

Fig. 18 is a detail view of a bracket structure.

. looking in the direction of the arrows i8|8 in Fig. 4; and

Fig. 19 is a diagram of shutter operation.

All the figures show the mechanism in the position it reaches at the endof the operation of winding the driving spring, ready for tripping;except Figs. 16 and 16a which show positions of the auxiliary shuttermechanism as the mechanism is being tripped, and Fig. 14 which showspositions of certain parts for moving the selector and release latchinto operative position.

The general sequence of the following detailed description will be asfollows:

I. The shutter mechanism proper, or shutter unit and the auxiliaryshutter.

II. The shutter driving mechanism.

III. The selector mechanism.

IV. Control and actuation of the selector mechanism, and free wheeling.

V. Auxiliary shutter actuation.

These divisions of description are not rigid, as certain parts havefunctions in more than one division, and as preliminary descriptivereferences to parts later described are found necessary to an easilyunderstandable exposition of the mechanism.

I. The rotating shutter unit In the drawings, numeral 20 designates ahorizontal frame plate, below which are the rotating shutter unit andshutter driving gearing, and above which is secured a housing 22 for theshutter driving and control mechanism. Plate merely typifies anysuitable mounting member or frame. It is not contemplated that theactual shutter mechanism will contain such a plate, but it is shown hereto indicate some means of supporting the mechanisms and to indicate theposition of an exposure aperture or axis.

The rotating shutter unit preferably comprises a high speed shutter,made up of a pair of concentric, oppositely rotating high speed shutterdisks and 25a, and a low speed shutter, made up of a pair of concentric,oppositely rotating low speed shutter disks 26 and 26a. The completeshutter mechanism also includes an auxiliary pivoted shutter blade orocculter 21 whose operation will be later described. The two oppositelyrotating high speed shutter disks have coacting exposure apertures 28and 28a, and the two oppositely rotating low speed shutter disks havecoacting exposure apertures 29 and 29a. The apertures in the high speeddisks, as well as those in the low speed disks, are so relativelypositioned as to register with one another once each revolution at thelocation of the exposure axis A. Frame plate 20 is shown as formed withan ex posure aperture 30 of suitable diameter concentric with axis A.

The two sets of shutter disks overlie one another at the exposureaperture so that the open ings in both sets must be over the aperture inorder to effect exposure. The high speed shutter disks revolve somedefinite whole number of times faster than the low speed disks (a factorof eight is preferably selected for the present design) so that there isthus, illustratively. one low speed shutter opening for eight potentialhigh speed shutter openings. The high and low speed shutter disks are sosynchronized that the occurrence of each low speed shutter opening atthe exposure axis coincides with the occurrence of every eighth highspeed shutter opening at the exposure axis. If the auxiliary shutter 2!is out of register with the exposure aperture when such coincidenceoccurs, an exposure results. The

operation is represented in the diagram of Fig.

19, where the angular rotation of the shutters is measured horizontallyand areas of the shutter openings are measured vertically. The 360 cycleof operation indicated represents one revolution of the low speedshutter disks and one low speed shutter opening, and eight revolutionsof the high speed shutter disks with eight potential high speed shutteropenings. As indicated, the low speed shutter opening occurs at the endof the I 360 cycle, and coincides with the last high speed shutteropening of the series.

Preferably, and as here shown, each shutter aperture is elongatedsomewhat in a direction circumferentially of the disk, is of a widthdimension w substantially equal to the diameter of the bundle of lightrays corresponding to the largest iris opening of the camera, and isbounded at the ends by arcs of radii equal to w/2.

The elongation of the high speed shutter apertures in the present designis preferably such that they each subtend a central shutter angle ofabout 95. and of the low speed apertures is preferably .such that eachsubtends a central shutter angle of about 65. By employing shutterapertures of the central angles mentioned, and utilizing an eight to onespeed ratio between high and low speed shutters. the high speed shutteropens and closes while the low speed shutter is at its maximum opening,and the low speed shutter opening does not overlap any portion of thepreceding or succeeding potential high speed shutter openings. See thediagram of Fig. 19. At the same time, by using shutter apertures of theshape and central angles stated, I accomplish a high speed shutterefficiency of about That is to say, taking into account that the area ofthe shutter opening defined by the two apertures of the high speedshutter disks increases and then decreases progressively as the shutterapertures move into and out of register, while remaining constant atmaximum opening for an intermediate interval, the shutter opening forthe entire period from the time the apertures begin to open to the timethey are finally closed is about 70% of what it would be if the openingwere constantly at maximum size for the full period.

During the operation of winding up the driving spring, the rotatingshutter unit is stopped and held by the selector mechanism (laterdescribed) in some selected position where the low speed shutterapertures are located somewhere between 0 and the position designatedLow speed shutter opening in Fig. 19. In this position the low speedapertures have less than 360 movement before reaching the designatedposition at which exposure takes place. The shutters having beenstopped, the driving spring is then wound through an angle commensuratewith the angle through which the low speed shutter is to be driven toreach the designated position. (As will appear, spring winding isstopped at 360 in the diagram). The selector mechanism which holds theshutters is then tripped to release them to be driven to and through theexposure position. As will appear, a trip shaft preferably performs thetripping operation. These functions are here preliminarily described sothat the general functions and timing of the auxiliary shutter may bepreliminarily understood.

The auxiliary shutter 21, which comprises in this instance a shutterblade 32 on an arm 33 pivotally mounted at 34, is normally in alinementwith exposure axis A, and thus normally prevents exposure even thoughthere should be a coincidence of high and low speed shutter openings atthe exposure axis. Just before the exposure is to occur, this auxiliaryshutter is withdrawn, and it is released and caused to move back intolight occulting position immediately the exposure is made, so thatfurther exposure of the film is prevented as the mechanism coasts to anindeterminate stop, even though there may be subsequent registrations ofboth high and low speed shutter openings at the exposure axis. Thesynchronizing relation between the shutter disks and auxiliary shutterwill be explained later in detail. It is sufficient at this point to saythat the auxiliary shutter is, as shown here, moved to its open positionby the tripping action that releases the shutters for driving, and isreleased to close in timed relation with the rotating shutters. Thisclosure release takes place immediately after the high speed shutteropenings have passed out of exposure register, at the point in Fig. 19designated auxiliary shutter released to close."

The shutter disks are driven from a gear 40 (see Fig. 6) on a gearsleeve ll rotatably mounted on the 1ower portion of a vertical deadshaft 42 that extends downwardly through an aperture 43 in the bottomwall 22a of housing 22. Gear 40 meshes with the upper one of twin gears44 (Figs. 3. 4 and 5) having a common hub 45 rotatable on axle 48mounted top and bottom in horizontal upper and lower frame plates 41 and48. The latter are supported at one edge on the top and bottom,respectively, of upper and lower channeled brackets 48 and 58, which arespaced by feet 48a on bracket 68 (see Fig. 18). Bracket 58 is suitablysecured to the bracket feet 48a, and the two brackets are securedthrough spacing blocks 5| to the underside of frame plate 28. The spaceso provided between the two brackets 49 and 58 accommodates portions ofthe high speed shutter disks. as will be evident from Figs. 3 and 4.Plates 41 and 48 are further supported by means of suitable connectingtie rods and spacers, as indicated at 52, and upper plate 41 is securedto frame plate 28 as by means of screws 54 and spacers 55 (Fig. 3).

Top twin gear 44 drives upper high speed shutter disk 25 through a geartrain (see Fig. 4) comprising gears 68, 6|, 62, 63 and 64, the lattercarrying the upper shutter disk. The axles of these gears, except 64,are mounted at the top in plate 41 and at the bottom in a sub-frameplate 65. as indicated. Lower twin gear 44 drives lower high speedshutter disk 25a through a gear train (see Fig. 5) comprising gears 18,H, 12, 13, 14 and 15, the latter carrying the lower shutter disk. Theaxles of the gears 18 to 14 are mounted at the bottom in frame plate 48.and at the top in a sub-frame plate 16. The gear train driving the lowerhigh speed shutter disk may be exactly like that driving the upper highspeed shutter disk, except for the addition of an idler gear whichreverses the relative direction of rotation of the lower disk. The twogear trains are such that both high speed shutter disks rotate at aspeed'ratio of two to one relative to driving gear 48.

Fig. 4a shows how the disk carrying gears 84 and 15 are mounted on acommon axle 46a between plates 41 and 48, and how the gears are spacedapart by spacer 11 between their bearings 18 so as to space the diskswith suihcient clearance to keep-them out of mutual contact. The shutterdisks are of thin sheet metal such as an aluminum alloy, so that theirmass and inertia are as small as practicable.

Top twin gear 44 also drives the upper low speed shutter disk 26 througha gear train comprising gears 88, 8I, 82, 83, 84 and 85, gear 85carrying the shutter disk; and lower twin gear 44 also drives lower lowspeed shutter disk 26a through a gear train comprising gears 86, 81, 88,88. 88, SI and 82, gear 82 carrying the shutter disk. See Fig. 3 for therelative vertical locations of the gears in these trains. These geartrains give a four to one speed reduction from gear 44 to the low speeddisks, and the lower train contains an extra idler gear which reversesthe relative rotation of the lower disk. The axles of the upper gearsare mounted in frame plate 41 and a sub-frame plate 84, and the axles ofthe lower gears are mounted in frame plate 48 and in a sub-frame plate85. The mounting of the two disk-carrying gears, and the disk spacing,is the same as before described for the mounting of the high speeddisks.

The several disks are so set on their carrying gears that the twoexposure openings of each set reach a position of full registrationcentered on the exposure axis; and so that each full registration of theset of low speed openings occurs simultaneously at the axis with a fullregistration of the high speed openings.

II. The shutter driving mechanism The shutters are driven by a drivespring H8 coiled about dead shaft 42 and connected at its lower end todrive the shutter driving gear sleeve H as will be explained. Shaft 42is supported at its lower end in a bracket III secured to a lug III I)that extends downwardly from bottom housing wall 221:, the lower end ofthe shaft being keyed against axial displacement as at IIIa. See Figs. 6and 8. A head H2 is rotatably mounted on the upper portion of shaft 42,the upper end of the spring being anchored to a stud H3 set into head H2as illustrated in Fig. 6. A spacing sleeve H4 disposed inside andextending substantially the length of coil spring I I8 is press fittedat its top into the lower end of head I I2, its lower end being pressfitted onto a flanged disk H5, which is rotatably mounted on shaft 42.Sleeve II4 supports spring II8 against collapse or buckling when placedunder substantial torsional strain, and also serves as a verticalsupport for the upper spring head H2. Disk H5 is supported by theillustrated series of bearings and spacer sleeves footing on the lowerbracket III (Fig. 6).

Upper spring head H2 has an upwardly extending hub I28 rotatablyjournalled in a bushing I2I set in a supporting plate I22 (see Figs. 6and 7), which is mounted in an opening formed in the upper wall 22b ofhousing 22.

Drive spring H8 is wound by rotating upper spring head H2. This may bedone either by power or by hand operationpfor simplicity a hand crank isillustrated for hand winding. The crank I32 is here shown as rotatablymounted on the upper end of shaft 42, being provided with a hub I33rotatable on shaft 42 between upper collar I34 and the hub I35 of aratchet disk I36 which is rotatable on the shaft 42 immediately belowthe crank. Ratchet disk I36 is engageable by a spring-pressed pawl I38pivotally mounted at I38 on crank I32, pawl I38 being supported on theunderside of the crank arm by a retainer plate I38a secured to the arm.The pawl transmits clockwise rotation from the crank to the ratchetdisk.

Ratchet disk I36 has a depending clutch jaw I 48 received between twocircumferentially spaced jaws HI and I42 which project upwardly from adisk I44 on the upper end of a sleeve I45 which is rotatably mounted onshaft 42. See Figs. 6, 13 and 3. A light coil spring I46 surroundingshaft 42 between disks I36 and I44 has its two outwardly bent endportions I41 and I48 (Figs. 3 and 13) in engagement with opposite sidesof jaws I48 and I, so as to hold said jaws normally in engagement. SeeFig. 13. The function of spring I46 i to rotate ratchet disk I36, andthe crank, backwardly (counterclockwise) relative to disk I44 when thecrank is free. When crank I38 is rotated in a clockwise direction,ratchet disk I36 is driven by crank carried pawl I38, and jaw I48carried by disk I36 separates from jaw HI and moves into engagement withjaw I42 (Fig. 14) after which disk I44 is driven from ratchet disk I36.Upon crank I38 being re leased, spring I46 returns the disk I36 to theoriginal relative position (Figs. 3 and 13).

The primary function of the two disks I36 and I44 and their relativemovements is to control the operation of the selector mechanism so as tomake that mechanism operative to cause spring winding only when thecrank is being turned and to provide for the free wheeling of the wholerotating shutter and drive mechanism at other times. These disks alsoperform a function in timing the selecting operation of certain parts ofthe selector mechanism. These functions will be described in detaillater along with the selector mechanism.

The lower end of sleeve I45 is keyed into the upper end of the hub I20of upper spring head II2, as indicated at I50 (Figs. 6 and 7), so thatrotation of crank I32 causes rotation of upper spring head H2, andtherefore of the upper end of main spring IIO which is anchored to thelatter.

Sleeve I45 is formed near its lower end with a gear I5I. to the lowerside of which is secured a ratchet wheel I52 (Figs. 6 and 'l). A pawlI53 pivotally mounted at I54 on mounting plate I22, pressed into ratchetengagement by a spring I 55, prevents reverse rotation of the upper endof the wound spring H0.

The lower end of spring H is anchored at stud I62 to a head I60journalled on shaft 42. The tubular lower end portion I63 of head I60 iskeyed at I64 to a gear sleeve I65 journalled on shaft 42. Head I60 andgear sleeve I65 are functionally a single member. The lower end of gearsleeve I65 is provided with a driving connection with the previouslymentioned shutter driving gear sleeve M. This driving connectionpreferably comprises a pair of engaging clutch Jaws I66 and I61 (Figs. 6and 8) formed on the lower end of gear sleeve I65 and the upper end ofgear sleeve 4|, respectively. A coil spring I68 surrounds shaft 42 withits two ends in engagement with the two clutch Jaws I66 and I61, in themanner illustrated in Fig. 8. so that the spring tends to maintain thejaws normally in driving engagement to transmit clockwise rotation fromthe driving spring to gear 40.

In the spring winding operation the spring is first rotated as a wholebefore the selector mechanism acts to stop the lower end of the springto cause spring winding. During this free spring rotation the shutters,geared to the lower end of the spring, also rotate. When that freerotation is suddenly stopped. sleeve 4| and the shutters have acquiredsome momentum. Spring I68 relieves the shutters of shock strain byallowing separation of clutch jaw I61 from clutch jaw I66. Spring I68then serves to return the parts to the relative positions of Fig. 8 whenthe momentum has been dissipated. Aside from thus allowing shutterover-run to dissipate shutter momentum, gear sleeve 4I functions as ifit were directly connected to, or a part of, lower spring head I60. Asit is. gear 40 and the shutters always rotate with the lower end of thespring except when the shutters temporarily overrun.

III. The selector mechanism Gear II on sleeve I45 at the upper end ofthe drive spring meshes with a gear I12, and the latter is fast with asmaller gear I13 that meshes with a gear I14 journalled on an upper endportion of a dead shaft I15 extending from top to bottom of housing 22in parallelism with shaft 42. This upper train of gears always rotateswith the upper end of the drive spring. Shaft I15 is supported at thetop in upper housing wall 22c, and at the bottom in a bearing cap I16secured to the lower wall 22a of the housing.

The gear I80, on the gear sleeve I65 which is connected to the lowerspring head I60, meshes with a gear I8I. and turning with the latter isa smaller gear I82 which meshes with a gear I83 surrounding the lowerend portion of shaft I15.

This lower gear train always rotates with the lower or driving end ofthe spring. Gear I83 is secured to a flange I84 on a sleeve I85 whichsurrounds shaft I15 and is journalled at its lower end on shaft I15 bybearing I81. This bearing, resting on the hub of bearing cap I 16, alsoacts as a thrust bearing to support sleeve I 85 and the parts carried byit.

An inner sleeve I3I surrounding shaft I15 within sleeve I05 is fitted atits lower end within sleeve I85, and at a point intermdiate its lengthwithin the reduced bore I9Ia at the upper end of sleeve I85. This sleeveI8I' has at its upper end an enlarged cup portion I82 receiving andsupporting the outer race ring of a bearing I93 surrounding shaft I15.Sleeve I9I may preferably flt tightly in lower sleeve I85, so thatwhenever the lower sleeve rotates (which it does during both shutterdriving and free wheeling) it will rotate on the well spaced bearingsI81 and I93. The inner race ring of bearing I93 supports the inner racering of the Journal bearing for upper gear I14. That bearing also actsto support gear I14.

The downwardly facing shoulder 2'00 presented by.the bearing cup I82 onthe upper end of inner sleeve I9I is engaged by the upper face of aflange 20I on the upper end of an upper sleeve 202 that is journalled oninner sleeve I9I between cup I82 and a centrally bored disk 204 mountedon the upper end of lower sleeve I85. In the construction illustrated,disk 204 has a depending tubular hub 205 receiving and keyed to theupper end of sleeve I85. The lower end of upper sleeve 202 iscounterbored to receive a bushing 206 and the upper portion of anabutting spacer bushing 201; and bushing 201 extends downwardly throughthe bore 208 of disk 204 and into a counterbore 209 in the upper end oflower sleeve I85.

The upper sleeve 202 is mounted for rotation relative to disk 204 andsleeve I85, but (Fig. 15) this rotation is confined to a few degrees bya stop lug 2I0 extending upwardly from disk 204 and received withsuitable clearance within a notch 2II formed in the lower end of sleeve202. Notch 2II provides two circumferentially spaced shoulders 2I2 and2I3 engageable by the ends of stop lug 2H), and a spring 2I4 coiledabout sleeve 202, with its upper and lower ends anchored to disks 20Iand 204, respectively, (see Figs. 3 and 15) tends to maintain the stoplug 2I0 against shoulder 2I2. That is, spring 2I4 tends to rotate uppersleeve 202 right-handedly with relation to the lower sleeve I85. In thecondition of the mechanism shown in the drawings, when spring 2I4 is notovercome by spring I I0, spring 2I4 rotates upper sleeve 202 relative toI85 through the small angle allowed. The purpose and action of thissmall movement will be explained later. For the time, this movement maybe ignored. For the moment and for the purposes of understanding thegeneral actions of the mechanisms, the two sleeves I85 and 202 may beconsidered as if they were integral or rigidly connected.

Disk 20I carries an upstanding abutment stop or shoulder 220, which isengageable with a similar abutment stop 22I extending downwardly from aplate 222 that is secured to the underside of gear I14. See Figs. 6 and11. In the unwound condition of the mechanism, abutments HI and 220 arein engagement with one another (see the dotted line position of stop 220in Fig. 11). Drive spring H0 is preferably under some initial straineven when the mechanism is unwound, and the force exerted by this springat such time maintains abutments 220 and 22I in engagement. The lowerend of the drive spring tends to drive lower gear I83 clockwise, andalso sleeve I85 and sleeve 202 and its abutment 220. The normal drivespring torque thus tends to move abutment 220 right-handedly againstabutment 22I and hold them in that engagement as shown in dotted linesin Fig. 11. If crank I32 is rotated to drive the upper end of the drivespring right-handed, and nothing is done to hold the lower end of thedrive spring, then main spring II- will simply be revolved as a whole,neither of its ends being held, and the gear train between the lower endof the spring and gear I83 will cause sleeves I85 and 202, and thereforeabutment 220, to revolve, while at the same time the gear train betweenthe upper end of the spring H0 and gear I14 causes the latter togetherwith its abutment 22I to revolve at the same speed, abutments 220 and22I remaining in engagement all the while.

It should be stated at this time that there is a four to one gearreduction between the upper and lower ends of drive spring H0 and therespective gears I14 and I83, so that the selector mechanism isgear-related to the winding crank and the driving spring in aone-to-four ratio. As has been stated, the high and low speed shuttersare geared to the driving spring in respective two-to-one andone-to-four ratios; so their geared ratios to the selector mechanismare, respectively, eight-to-one and one-to-one. When the whole mechanismis rotated freely, as above stated, the shutters of course rotate withit in the ratios stated: but when the lower end of the drive spring isheld, by functions in the control mechanism to be explained, theshutters are also held stationary.

Splined on sleeve I85 is a circular rack gear 230, meshing with anoperating pinion 23I mounted on a shaft 232 which is journaled inhousing 22 and has on one end an operating crank 233 (see Figs. 1, 2 and3). Crank 233 has a spring pressed pin 236 which can be withdrawn byoperation of head 239 and registered in any one of the spaced holes 231in the adjacent casing wall. Stops 240, or any other suitable means,limit the adjusting movement of crank 233 and rack 230.

Operation of crank 233 thus rotates pinion 23I to elevate or lower rack230. The upper end of the rack is formed with an outwardly extendingannular flange 245, to which is secured a winding tension selector 246.This selector 246 has a cylindric wall 248 formed at the top with a steplike formation providing a series of circumferentially spaced stopshoulders 250 at progressively higher elevations (considered in acounter-clockwise direction circumferentially) there being six suchshoulders in the illustrated embodiment. See Figs. 6 and 12. There is avertical drop-edge 25I between the last or highest and the first orlowest of the shoulders 250, as will be clear from inspection of Figs. 3and 6.

To the right of shaft I15, as viewed in Fig. 6, are three verticalshafts 260, 26I and 262, positioned as illustrated in Figs. 9 to 12.These shafts are journaled in suitable bearings carried by a pair ofvertically spaced mounting plates 265 and 266 that are secured tohousing 22 in suitable manner.

The release shaft 260 carries at the bottom a selector engaging arm 210shaped at the tip for engagement between the teeth of rack 230; ro-

tation of shaft 260 moves arm 210 between positions of engagement anddisengagement with the rack 230. Vertical adjustment of rack 230 must bemade with arm 210 swung out of engagement therewith, and after rack 230is vertically positioned, and arm 210 has then been moved into properengagement with it, the rack and selector 246 are locked against furthervertical movement. See Fig. 12 for the two positions of arm 210. Arm 210registers with the spaces between the rack teeth in positions of therack in which the plunger pin 236 of adjustment crank 233 is in registerwith holes 231. If such registration does not exist, arm 210 will strikethe ends of the rack teeth and will not move into locking engagementwith the rack. When that registration does exist, one or another of theselector shoulders 250 is at the proper elevation to be engaged by theselector stop and release latch 212 which moves with arm 210. Thegeneral functions of arm 210 are to prevent engaging movement of theselector and release latch unless selector 246 has been properlyadjusted; and to prevent any further adjustment 'movement of theselector after operation of the mechanism has commenced and arm 210 andlatch 212 have moved to engaging position.

Release shaft 260 carries, just above mounting plate 266, a selectorstop and release latch 212, conveniently hereinafter referred to simplyas the release latch. correspondingly, the shaft 260 carrying latch 212is conveniently designated the release shaft, although its function alsoincludes the operation of latch 212 to engage and stop the selector 246.Release latch 212 has a hook portion 213 at the end adapted, when thelatch is swung from the dotted line to the full line position of Fig.12, to engage the selected one of the stop shoulders 250 on the selector246, it being understood that vertical adjustment of rack 230 in themanner above described brings the several successive shoulders 250successively to the level of release latch 212. See Fig. 6 which showsthe relative level of latch 212. This figure and Fig. 12 show theselector and the latch, in full lines, in position where the latch hasengaged the third lowest shoulder 250 on the selector. Arm 210 andrelease latch 212 are so positioned on shaft 260 that the release latchmoves into the selector stopping position of Fig. 12 as the arm 210moves into engagement with rack 230, so that the same rotation of shaft260 locks the rack and the winding tension selector against furthervertical adjustment and throws the release latch 212 into position toengage the selected stop shoulder 250 on the selector during thesubsequent rotation of the selector. When the selector 246 and releaselatch 212 have been set, operation of the winding crank will firstrotate the drive spring and selector mechanism bodily until latch 212engages a winding selector shoulder. The latch then holds the sleeve Iand 202, and the lower end of the drive spring, against further rotationwhile the drive spring is wound up by an amount which depends on theposition of the parts when latch 212 engaged the selected shoulder 250.The stop which limits the spring winding operation is relatively a fixedposition stop. The amount by which the drive spring is wound dependssolely on the position of the parts when winding begins; selected byoperation of selector 246.

The advance end 280 of stop plate 222 on upper gear I 14 serves as awinding stop, being engageable in a predetermined position of rotationof gear I14 with the hooked end of a winding stop latch 28I which ismounted on shaft 28I (Fig. 11). Latch 28I is provided with a projection282 working in a slot in a block 285. Spring 283 seated in that blockacts to urge the latch to move to latching position. A stop 284 formedon the hub end of latch 28I is engageable with block 285 to limitmovement of the latch past its stop engaging position.

To avoid engagement between the winding stop latch 28I and the windingstop 288 at any time except when the winding tension selector 246 hasbeen engaged by the release latch, the disk 284 on lower sleeve I85 isfurnished with a cam plate 281 (Figs. 6 and 12) which engages a roller288, carried by an arm 289 on shaft 28I, and rocks shaft 28l to withdrawstop latch 28! to the dotted line position each time the stop 288 passesby. When, however, the winding tension selector 248 has been stopped byrelease latch 212 and spring winding has commenced the cam plate 281 isof course stopped with it, and winding stop latch 28l accordinglyremains in position to engage stop 288 and so stop the winding of thespring. Cam plate 281 is only effective to disable the winding stoplatch 28I when the cam plate is in a position synchronized with themovin winding stop 288; that is, when abutments 228, Ml are inengagement.

The general function of the parts just described is to make the windingstop inoperative whenever abutments 228, 22l mutually engage. and othercontrol mechanisms may be used instead of that described, which ismerely typical. And it may also be remarked that winding stop 28I may byits movements perform additional functions in a complete cameramechanism, not necessary to be described here.

Preferably the movement of release latch 212 to selector stoppingposition (full line position of Fig. 12) is timed by control mechanismdescribed later to occur just after the vertical edge 25I of theselector has passed the location of the release latch. The stopshoulders 258 pass successively below the release latch until theparticular shoulder adjusted to the level of the release latch arrivesat the release latch and is stopped thereby. The winding stop 288 andwinding stop latch 28I are so positioned with relation to selector edge25I that the stop 288 will not engage latch 28I until nearly 360 oftravel (preferably about 354") following projection of the release latchinto selector stopping position. After projection of the release latchinto the path of the selector, the selector revolves until the selectedstop shoulder 258 reaches and engages the release latch. This actionstops the rotation of the selector, the lower end of the drive spring,sleeve 282 and abutment 228. Continued operation of the winding crankI38, then continues to rotate the upper end of the spring and the uppergear I14, so that the abutment 22I moves away from abutment 228 in aclockwise direction. Finally. after about 354 of rotation of the windingstop following projection of the release latch into the path of theselector, the winding stop is engaged by winding stop latch 28I, andwinding of the spring is arrested. The tension in the spring I I8 willnow depend upon which one of the shoulders 258 of the winding tensionselector was in position to engage the release latch 212, or in otherwords, upon how far the upper end of the spring was turned to bring stop288 up against stop latch 28I after release latch 212 engaged theselected shoulder 258. Fig. 12 shows release latch 212 engaging aselected stop shoulder on selector 245, and that figure and Fig. 11 showthe position of the parts when spring winding has proceeded to its end,stop 288 and abutment 22I have rotated clockwise away from abutment 228through an angle which has been determined by the selected selectorshoulder 258, and winding stop 288 has finally brought up against stop28I. The whole mechanism is then held in this position by the releaselatch 212 and the ratchet pawl I53; the former preventing clockwiserotation of the lower end of the drive spring and of the selectormechanism, and the latter preventing retrograde movement of the upperend of the drive spring and of gear I14 and abutment 22I.

Upon subsequent withdrawal of release latch 212 the selector mechanismwill be freed to rotate and allow the lower end of the spring to drivethe shutters through an angle determined by the angle through whichabutment 228 rotates clockwise to reach the dotted line position in Fig.11, against abutment 22I.

A summary of operation of the mechanisms so far described may now bemade.

When the mechanism is at rest after a previous operation, the shutterdisks may have any position relative to the exposure aperture, due tothe fact that the mechanism has finally come to rest at the end of afree wheeling run. Normally, the first operation is to set the selector246 to the exposure desired. Then the winding crank is operated.Disregarding for the moment the initial relative movement between thescalloped disks I38, I44, rotation is thus transmitted to the drivingspring. As stated before, the initial tension on the driving springholds abutments 228, Ml together, and in this condition the drivingspring, the upper and lower gear trains, and the rotatable selectormechanism form a closed train revoluble as a unit without any relativerotation between its parts. For the moment, spring 2 and the limitedfreedom between lower sleeve I and upper sleeve 282 may be disregarded.The tension of the drive spring, stronger than that of spring 2 andacting against it, throws jaw 2I8 by relative clockwise rotation againstshoulder 2I3, in this condition of the mechanism.

Thus, at first, and until rotation of selector 246 is stopped, the wholeclosed train is merely rotated. If the selector has not been set inproper position to allow the selector and release latch 212 to move in,this free wheeling operation may go on indefinitely. But, assuming thatthe selector has been properly set to allow latch 212 to move in toengage a selector shoulder, then the following sequences occur as soonas latch 212 is moved in, or released to be moved in by a spring.

Regardless of when latch 212 is released to move in (it is onlypreferable that it be timed to move in directly after selector edge 25Ihas passed it) the selected selector shoulder 258 will then engage itthe first time that shoulder comes around after the latch moves in. Theimmediately previous passage of selector edge 25I past thelatch'corresponds to 0 in the diagram of Fig. 19. In this position ofthe mechanism the shutter disks have just completed an exposureregistration with the exposure aperture, but with auxiliary shutter 21closed, and will not make another exposure registration until near theend of the 360 cycles. Latch 212 then engages the selected shoulderafter rotation through the selected angle following the last previousshutter disk registration.

Due to the fact that the separable abutments 220, Hi are located in therotatable train between the selector and the upper end of the drivespring, and to the fact that the forward abutment 22I (forward in thedirection of clockwise rotation) is connected to the upper end of thespring so that the stops separate by relative forward movement of thatone, the shutters are now held stationary at the selected position inthe 360 cycle while the upper end of the drive spring rotates on to theend of the cycle where it is stopped by the winding stop latch "I andheld from backing up by pawl I53.

Release of the mechanism for effecting an exposure then consistsessentially in opening the auxiliary shutter and in moving latch 212 outof selector engagement. The auxiliary shutter can be opened at any timebefore exposure. Its preferred operation will be explained later; itsaction is such that, at the moment, it may be considered as if it wereopened by hand at the time of or before releasing latch 212. If latch212 is then released and held out (the control mechanisms forautomatically holding the latch out as well as for timing its movementinward will be later explained) then the following operations takeplace.

The released lower end of the driving spring drives the shutters forwardfrom their stopped position. The shutters are thus accelerated, and thespeed which they reach depends upon the strain that was put in thespring III) and the angle through which the shutters are driven, boththese factors having been determined by the particular selector stopshoulder 250 which was selected and utilized to arrest rotation of thelower end of the spring. The spring reaches its relatively unwoundcondition at the time abutment 220 re-engages abutment I, the shuttershaving at this time attained maximum speed for the particular selectorshoulder 250 that was used. Re-engagement of abutments 220, Hi takesplace in the diagram (Fig. 19) at 360, if the small relative movementindicated in Fig. 15 be still disregarded. The timing of the mechanismis such that at this same time, or preferably just shortly before, thehigh and low speed shutter openings occur at the exposure axis (Fig.19), and an exposure is had. Immediately after exposure the auxiliaryshutter is closed by a time control mechanism (explained afterwards)which closes that shutter before the rotating shutters next againregister in the ensuing free wheeling movement now to be described.

Just before abutments 220, Ml reengage, cam plate 281, which is thenmoving ahead to its normal synchronized relation to stop 280, lifts thewinding stop latch 28I to free the upper parts of the rotary train forforward movement. See Fig. 19 which indicates that cam 28'! lifts thestop latch just ahead of reengagement of abutments 220, Ml. Abutments220, I having come into reengagement, the momentum of the rotating partsof the mechanism is in part transferred to the previously non-rotatingparts, and the then closed train begins again to rotate as a whole infree wheeling. Cam 281 being now in synchronized relation to movingwinding stop 280, lifts the winding stop latch I on each revolution toclear stop 280. The mechanism continues to free wheel until its momentumis absorbed by frictional losses and by incidental energy expendituressuch as that which is caused by cam 28! moving arm 289 and winding stoplatch 28I (see Figs. 11 and 12) once each revolution. The rotatingmechanism, including the rotating shutters, thus come to a final stop inan indeterminate position, as mentioned before.

If desired a brake may be provided to bring the rotating parts morequickly to a stop. As here shown, the stationary mounting plate I22 atthe upper end of the driving spring supports springs 215 which engage astationary friction washer 216 keyed at 211 to the plate and bearingagainst a friction washer 218 which is fast to the upper spring headII2. This friction mechanism exerts a light but constant frictional dragon the rotation of the upper end of the driving spring. Consequently itexerts that frictional drag on the mechanism only when the rotatingtrain is rotating as a whole, which it does in free wheeling. During theperiod when the shutter is being driven by spring energy, the frictionbrake is inoperative, the upper end of the driving spring is thenstationary.

The operation of the mechanism has so far been considered as if therewere no movement freedom between lower sleeve I and upper sleeve 202,but as if the two sleeves were relatively rigid or integral. The reasonfor preferring a slight spring opposed relative movement between the twosleeves will now be explained. As stated before, the initial tensiontorque of drive spring I I0 is greater than that of spring 2.Consequently, whenever abutments 220, Ml are in engagement, as when themechanism is at rest or is free wheeling, spring IIO overcomes thetorque of spring 2 and moves the lower sleeve I85 an its upper disk 204and clutch lug 2I0 righthandedly with relation to upper sleeve 202.Under these conditions the clutch lug 2IIl engages shoulder 2I3 in Fig.15. However, as soon as lower sleeve I85 has been stopped from rotationby the selector action, and the torque of the drive pring thus taken offspring 2, then as abutment 22I leaves abutment 220 in right-handeddirection, spring 2 moves the upper sleeve 202 around in a right-handeddirection until its shoulder 2| 2 engages lug III] which in thenstanding still with lower sleeve I85.

At the end of the shutter driving operation, the abutment 220 reengagesabutment MI by moving up on the latter in clockwise direction. At thetime of that engagement, the right-handedly rotating abutment 220 moreor less instantly imparts rotary momentum to the previously statlonaryupper train of gears and the upper end of the drive spring. Th torque ofdrive spring IIIl immediately tends to move lug ZIIl righthandedly inFig. 15 into engagement with shoulder 2I3. Spring 2 however opposes thatrelative movement, as well as the reaction force on abutment 220 when itpicks up abutment MI. The slight relative movement opposed by the spring2 thus acts as a snubber on drive spring I II) to absorb at least aportion of the shock that would otherwise attend starting the upperparts of the mechanism into rotation, and thus takes shock off the wholemechanism as the whole mechanism starts free wheeling after exposure.Spring I68 takes the shock off the light thin shutter disks, but ifspring I68 be not used, spring 2 will perform that function. Other thanfor this desirable function of eliminating the effects of shock, the twosleeves I85 and 202 might, in full effect, be integral.

The slight relative movement involved in this action of absorbing shockhas only one effect, and is immaterial on the timing of action of thewhole mechanism. When upper sleeve 202 and its abutment 220 are movedslightly right-handedly by the action of spring H4 at the beginning ofthe spring winding operation, abutment 220 is thus put in a positionrelative to lower sleeve I85 a few degrees in advance of what itsposition would be if the abutment were fixed relative to lower sleeveI85. Abutment 220 consequentl engages abutment 22I at the end of theshutter driving operation a few degrees before the then driven part ofthe mechanism reaches the 360 point in the diagram of Fig. 19. It isthrough the last few degrees of rotation of lower sleeve I85 that driving spring I I is snubbed and the shock absorbed. the lug 2I0 of Fig. 15finally coming into engagement with shoulder 2I3 of upper sleeve 202 atthe 360 point in Fig. 19. But the arrangement is such that this relativeshock absorbing movement all takes place in Fig. 19 after the shuttershave been rotated through their position of complete closure of theexposure opening, which is shown as taking place at about 354.

IV. Control and actuation of the selector mecha nism and free wheelingThe description so far has been based on an assumption that the selectorstop and release latch 212 may be operated in any desired or suitablemanner, even by hand. I will now describe the preferred actuating andcontrol mechanisms by which the release latch is automaticallycontrolled, locked in selector engaging position sub- Ject to manual orother release, automatically moved to selector engaging position, andautomatically held out to allow the ensuing free wheeling. The primarypurpose of these mechanisms is to actuate the latch automatically and atthe same time automatically to provide for free wheeling. Incidentallythese same mechanisms time the movement of the latch into selectorengaging position.

In the present preferred design of the mechanisms, release latch 212 hasa tail piece 330 formed at its extremity with an arcuate edge 33I whcihis preferably centered on the center of trip shaft 262 when the releaselatch is in the full line position of Fig. 12. A locking arm 332 rigidlymounted on trip shaft 262 has a correspondingly arcuately faced lug 333adapted to ride over the arcuate edge of the latch tail piece when thelatch is in position to engage the selector, full line position of Fig.12. Locking arm 332 has an integral projecting lug 335, and spring 336which is set in mounting block 331 presses against lug 335 to movelocking arm 332 into locking engagement with the latch tail piece. Thetrip shaft is rotated to unlock an trip the release latch 212 byrotation to the dotted line position of Fig. 12, by means of a handle262a (Fig.6).

Spring 338 mounted in block 339 acts against atch tail piece 330 in adirection to move release latch 212 to and hold it in its releasposition (dotted lines in Fig. 12).

As stated before. the release latch might be moved to its selectorengaging position by any means, and at any tme after the selector hasbeen properly adjusted. It is preferred however to make this se ectorengaging movement of the latch automatic: and in the present preferreddesign of the mechanisms it is preferred to utilize the cranking actionpreliminary to spring winding to control or actuate the movement of therelease latch into selector engaging position. By thus utilizing thepreliminary cranking action as the controlling means for that latchmovement, it will be seen that provision is made so that, except at atime during actual cranking, no force is exerted on the release latchtending to move it into selector engaging position, and consequentlythat the free wheeling action is allowed without any liability of thelatch reengaging the selector.

Release shaft 260 has the hub 290 of a rocker arm 29I rotatably mountedon its upper end. See Figs. 1, 6, 13 and 14. The lower edge of hub 290has a downwardly projecting clutch jaw 292 (Figs. 6, 13, 14) which isengageable with an upwardly projecting clutch jaw 293 on a hub 294tightly mounted on release shaft 260.

Rocker arm 29I (see Figs. 13, 14) is connected by link 3I0 with aswinging arm 3II which is pivotally mounted at 3I2 on the housing top.Arm 3II carries a roller 3I5 bearing on the periphery of disk I44 which,as will be remembered, always rotates with the upper end of drive springH0. Roller 3I5 also overlies a portion of the periphery of disk I36(Fig. 6), and disk I36 is preferably slightly smaller in diameter thandisk I44 for a reason later to be stated. Disk I36, it will beremembered, is the one which is rotated right-handedly from crank I32through the medium of a ratchet, and has a certain amount of lost motionwith relation to disk I44.

Roller 3I5 is pressed against disk I44 by a tension spring 3I6. Theperipheries of disks I36 and I44 are provided each with a singledepression or scallop, 3I8 and SIB, respectively. When these scallopsare registered (Fig. 14) roller 3I5 may enter and thus permit movementof arm 3 toward the left under the influence of spring 3I6.

Spring I46 acting between disks I36 and I44 normally holds the disks inthe relative positions shown in Fig. 13, with clutch jaw I40 againstclutch jaw MI, and scallops 3I8 and 3I9 out of mutual register so thatroller 3I5 cannot enter either scallop because it then rides on theperiphery of one disk or the other throughout the revolution of thedisks.

Initial rotation of winding crank I32 moves clutch jaw I40 around in aright-handed direction to engage clutch jaw I42, and moves the twoscallops into register. Then, if the registered scallops are not underroller 3I5, further righthanded rotation of both disks I36 and I44 fromthe position in which disk I44 happened to stop after the previousoperation will bring them both into register with roller 3I5, and spring316 may then move arm 3II to the position of Fig. 14. This springimpelled movement of arm 3II may occur on the first registry of theregistered scallops with roller 3I5 or on any subsequent registry whichoccurs during the rotation of the registered scallops under power fromthe crank. A timing mechanism, to be described, determines when thisaction will take place to move release latch 212 into selector engagingposition. Without the timing mechanism, the action would take place thefirst time the registered scallops register with roller 3I5. With thetiming mechanism. the action now to be described may take place at anyone of several successive registrations of the scallops with roller I35.

As will be pointed out later, release latch 212 is left in the dottedline position of Fig. 12, disengaged from the selector, at the end of aprevious completed operation. Fig. 13 shows the corresponding positionof clutch lug 293. When spring 3I6 moves roller 3I5 into the registeredscallops and moves arm 3| I andlink 3| 9 to the left, as in Fig. 14,clutch lug 292 is moved right-handedly against clutch lug 293 to rotaterelease shaft 269, release latch 212 and the selector locking arm 219.to the full line position shown in Fig. 12. Spring 3I6 is strong enoughto overpower the release latch spring 338.

Once the release latch is moved to its selector engaging position, andlocked in that position by the locking arm 332 on trip shaft 262,subsequent oscillations of rocker arm 29I and clutch lug 292 due to theintermittent entry of roller 3I5 into the registered scallops, duringthe time that winding crank I 32 is being subsequently rotated to windthe spring, will have no effect on release shaft 269. because of thelost motion between lug 292 and lug 293.

Hub 294 fast on release shaft 269 (see Figs. 6

and 9) carries a latch lug 295 engageable by latch hook 296 of a latch291 which is loosely pivotally mounted on shaft 26I. Latch 291 has acamming edge 299 engageable once each revolution of gear I14 by anactuating pin 399 mounted on the upper side of that gear. In Fig. 6 pin399 is shown in riot-dash lines, as being on the near side of thesectional plane of that figure.) Latch 291 has a projection 39I workingin a slot in block 285 (see also Fig. 3), engaged by Spring 393 seatedin the block and acting to move the latch in a direction to engage theactuating pin 399, and to move into latching engagement with latch lug295. Latch lug 295 is so located on release shaft 269 that when engagedby latch 291 (dotted line position to Fig. 9) the release latch 212 andselector locking arm 219 are held in the retracted dotted line positionsof Fig. 12. Engagement of latch 291 by pin 399 moves that latch to thefull line position of Fig. 9, thus releasing latch lug 295 and freeingthe release shaft 289 to be rotated right-handedly by the mechanismspreviously described. to move release latch 212 and locking arm 219 intothe full line operating positions of Fig. 12.

Pin 399 is so positioned on gear I14 that latch 291 frees the releaseshaft for right-handed rotation at a time when the vertical edge 25I ofselector 246 has just passed the release latch hook 213. abutments 229and 22I then being in engagement. (Fig. 9 shows the position at whichlatch 291 has just released: which position is substantially the same asthat shown in the other figures-the position in which gear I14 has madeone more complete revolution and has been stopped by the winding stop.)Vertical edge 25I of the selector passes the release latch hook approxmately or precisely at the 0 point in the diagram of Fig. 19: and therelease shaft is freed by latch 291 a few degrees later, about 6 in thisparticular design.

Disks I36 and I44 revolve four times for one revolution of gear I14. Thescallops on those disks are so positioned that they re ister with roller3I5 in synchronism with the releas ng action of latch 291. Latch 291,blocking the righthanded rotation of release shaft 269 until selectoredge 25I passes the release latch hook for the first time. it will beevident that the re istered scallops may pass roller 3I5 as many asseveral times before latch 291 unlocks the release shaft to move releaselatch 212 into operative position immediately behind the selector edge25I, all depending upon where the mechanism happened to stop at the end01 the preceding operation,

The purpose of utilizing the timing mechanism shown in Fig. 9 is toprevent release latch 212 from dropping in at a time when its hook endwould be spring-pressed against the outer periphery of selector 246 andthen pressurably ride the selector until its hook drops over edge 25I.As the mechanism is preferably designed, the release latch is moved intooperative position just prior to the arrival of the first or lowestselector stop shoulder 259 at the radial plane of the release latch hook213.

It will be remembered that selector locking arm 219, and thereforerelease latch 212, cannot be moved into their operative positions unlessselector rack 239 is properly adjusted and registered for properengagement of the release latch with one or the other of selectorshoulders 259. Seeing that locking arm 219 and release latch 212 aremoved into their operative position by spring pressure, arm 219 willblock the inward movement of latch 212 unless arm 219 can enter properlybetween the teeth of the selector rack.

As soon as release latch 212 has moved in to its operative position,locking lug 333 on trip shaft 262 immediately locks the release latch inits operative position. Continued rotation of the winding crank thenbrings the selected one of selector shoulders 259 up against the releaselatch hook, and then completes the winding of the drive spring, asbefore described. The mechanism is then in condition for subsequentexposure release as before described, by rotating trip shaft 262.

Preferably, a means is provided for positively preventing rotation oftrip shaft 262 to trip the release latch 212 until drive sprin H9 isfully wound, thus assuring that the spring tension for which theselector 246 was originally set is actually reached and used. For thispurpose, as here shown, there is tightly mounted on trip shaft 262 alatch lug 349 (see Fig. 19) engageable by the hook end 34I of a tripshaft latch 342, the latter being freely pivotally mounted on shaft 26I.Latch 342 has a projection 344 receivable in a slot 345 of block 285,and engageable by a spring 346 which urges the latch to move intolocking engagement with trip shaft lug 262. A tail piece 341 on thelatch is engageable with the side of block 295 as a stop. The describedlefthanded rotation of trip shaft 262 as lockin arm 332 moves intolocking engagement with release latch 212 moves latch lug 349 on thetrip shaft from the dotted line to the full line position of Fig. 19,whereupon spring 346 moves latch 342 into locking engagement with lug349 (full line position of lug 349 and dotted line position of latch 342in Fig. 10). The latch 342 has a camming edge 348 engageable by the pin399 on gear I14, and is movable by said pin from the dotted line to thefull line position of Fig. 10, so as to disengage latch hook 34I fromlug 349, and thus unlock trip shaft 262 for rotation in a righthandeddirection. This occurs just at the time the spring II 9 is fully wound;simultaneously with, or just prior to, engagement of stop 289 withwinding stop latch 2! (Fig. 11).

The sequence of operation is a follows: Assuming that the selector hasbeen properly set. then as crank I 32 is turned, release shaft 269 isrotated upon passage of registered scallops 3I8 and 3I9 past roller 3I5and simultaneous engagement and movement of latch 291 by pin 399 (Figs.9 and 14). This moves release latch 212 to its advanced, selectorstopping position, and the latch is immediately locked in that positionby trip shaft lock arm 332 (Fig. 12). The locking rotation of trip shaft262 causes locking of the trip shaft by latch 342 (Fig. releasable onlyby spring winding being subsequently completed. At the time the releaselatch and trip shaft are locked the drive spring III) is still entirelyunwound Iexcept for its initial strain). the abutments 220 and HI arestill in engagement, and the winding tension selector 246 is in aposition with its first or lowest stop shoulder 250 in a positionimmediately coming on to the release latch (though of course notnecessarily adjusted to the level of the release latch). Furtheroperation of crank I then brings selector 246 around until the stopshoulder 250 adjusted to the level of the release latch engages thelatter. and the rotation of selector 246, the abutment 22D. and thelower end of spring H0 is then stopped. Continued cranking thencontinues to turn the upper end of the spring, winding it up, and theabutment 22I during this time separates from abutment 220. This windingoperation is finally stopped as stop 28!! engages winding stop 28I (fullline position in Fig. 11). At this same time, as previously stated. tripshaft latch 342 is retracted by pin 300, unlocking trip shaft 262 (Fig.10). The mechanism is then released by rockin trip shaft 262right-handedly. Such movement of trip shaft 262 removes trip shaft arm332 from its locking engagement with the projection 330 of release latch212, whereupon release latch 212 is immediately moved by its spring 338to its dotted line or release position (Fig. 12). The hook end 213 ofrelease latch 212 engages stop shoulder 250 along a line which is radialof the center of rotation of selector 246. and the center of rotation ofrelease latch 212 being outside a line drawn tangent to the selector atthe location of the engaged stop shoulder, it will be evident that theselector itself, acted upon by the pressure of the tensed spring IIO.exerts a counter-clockwise moment on release latch 212, tending to throwthe release latch out of engagement with the selector once the releaselatch is disengaged by the lock arm 332. both by this counter-clockwisemoment exerted by the selector, as well as by its spring 338, thus movesfrom the full line to the dotted line position of Fig. 12, releasingselector 246 and the lower end of the spring for rotation. The shuttersare then driven from the lower end of the spring as before described.abutment 220 rotating with the selector and with the lower end of thespring to finally strike abutment 22I and so to set gear I14, andtherefore gear I5I, d sks I44 and I36, and the upper end of spring IIIlinto rotation. Free wheeling operation then takes place as beforedescribed. and the whole rotating mechanism stops indeterminateiy.

Normally it is to be expected that the winding crank will have beenreleased before the mechanism is tripped: but it is immaterial whetherthe crank is allowed to go free or is held. If the crank is freed at theend of spring winding. spring I46 will immediately rotate upper disk I36and the crank to a position where the scallops are out of register, orat least tend to do so. In any case, as disk I44 starts to rotateforward in the free wheeling operation, spring I46 (and also the drag ofthe crank pawl on upper disk I36) cause that upper disk to moverelatively behind lower disk I44 and the scallops thus are moved andkept out of register during free wheeling. This prevents roller I fromentering into the scallops during the free wheeling op- Release latch212. acted on -2- eration, and so spring 3I3 cannot act to move releaselatch 212 into engagement with the selector although pin 300 isperiodically unlocking the release shaft on each of the free wheelingrevolutions of gear I14. It is to assure the reverse rotation of diskI36 relative to disk I44, to the relative position of Fig. 13, that thedisk I36 is preferably made just slightly smaller in diameter than diskI44, thereby avoiding any possible frictional drag between roller I35and the periphery of disk I36.

After tripping, the release latch remains in its release position andthe trip shaft 262 remains in its position rocked toward the right byreason of engagement of the end of tail piece 330 of release latch 212with trip shaft arm 332 (see dotted line position, Fig. 12) until therelease latch is again advanced to selector stopping position in asubsequent operation.

The counter-clockwise selector releasing movement of release latch 212rocks release shaft 260 back to a position in which its latching arm 295is again engaged by release shaft latch 291 (Fig. 9), so that therelease shaft is again locked, in readiness for the next windingoperation to begin.

The operations of the mechanism have been described for hand winding andtripping. Winding and tripping may however be by power actuation,automatically controlled and timed, or controlled by remote control. Anysuch power actuation and control may be used as may be convenient ornecessary for actuation of the shutter mechanism in any desired system.With such matters my invention is not directly concerned, nor is itlimited in that regard.

V. Auxiliary shutter actuation So far, the descriptions of operationhave assumed that auxiliary shutter 21 is moved to open position at anytime previous to the exposure registration of the rotating shutters. andis then closed before the low speed shutter disks have again come toexposure position. For automatic operation of the auxiliary shutter, itmay be opened by virtue of any action that takes place in the mechanismbefore actual exposure, and it may be closed by any action taking placein timed relation to the exposure operation. Preferably the auxiliaryshutter is opened by an action which takes place before shutter drivingcommences, so as not to place a load on the mechanism during the actualdriving operation. Thus the auxiliary shutter is preferably opened bysome action connected with release of the mechanism for shutter driving:and in this present preferred design it is opened by the releasingaction of the trip shaft.

It may here be remarked that one reason for driving the low speedshutters through an angle of less than 360 is that they do not thencross the exposure axis before exposure is intended to occur.Consequently the automatic opening of the auxiliary shutter does nothave to be actuated by the mechanism while it is driving the shutters,and the auxiliary shutter can thus be opened by any operation whichoccurs before driving starts.

Arm 33 of auxiliary shutter 21 is secured to a flange 98 on the lowerend of a hub 99 that is rotatable on an axle I00 secured at the top toand extending downwardly from frame plate 41, as illustrated in Fig. 17.Hub 99 is formed at the top with an upward arcuate extension IOIconcentric with the hub. See Figs. 1, 16 and 16a.

This extension IOI, which serves as the member through which theauxiliary shutter is drawn aside, passes through an arcuate slot I02 inframe plate 41, and through aperture I03 in frame plate 20, so as torise above the plane of the latter, as appears in Fig. 17. A tensionspring I04 connected between extension IM and a post I05 secured toframe plate 41 holds the auxiliary shutter 32 normally in a positionalined with exposure axis A, the arcuate extension IOI engaging the endof slot I02 as a stop in such position (see Fig. 4).

In accordance with the present preferred embodiment of the invention,the auxiliary shutter is moved to one side during and by virtue of theinitial rotation of trip shaft 262 in the action of tripping the releaselatch of the mechanism. Thus, as shown in Fig. 6, the lower end of tripshaft 262 carries a rock arm 35i0 (see also Fig. 16), which is pivotallyconnected at 35I with a shutter setting arm 352. Arm 352 has at itsforward free end a hook portion adapted for engagement of one edge 353of the arcuate lug IOI of shutter hub 99. This hook portion, as hereshown, comprises a lug 354 on the underside of the arm at its forwardextremity, formed with a concave surface 355 adapted for engagement withthe lug edge 353. Lug 354 is here shown as slidably supported on frameplate 20, and the arm 352 is confined against separation from plate 20by an overlying guide 356.

A roller 310 mounted on frame plate 20 and a coacting cam surface 31I onarm 352 guide the arm in its various movements, and arm 352 is heldagainst the roller by means of a spring 312.

As stated before. auxiliary shutter 21 is normally in the lightocculting position of Fig. 1, being yieldingly held in such position byits sprin I04 (Fig. 1'1). When the trip shaft 262 rotates in acounterclockwise direction, to engage its lock arm 333 with releaselatch 212 at the beginning of the spring winding operation, the arms 350and 352 move to the position of Fig. 1. In the course of such movement,the concaved forward corner 380 of arm 352 rides against the arcuateshutter operating lug IIJI. As the position of Fig. l is approached, thehook surface 355 moves beyond edge 353 of lug IN, and the deep portion38I of cam surface 31I permits arm 352 to move laterally, so as to movesurface 355 beyond the lug edge 353, arm 352 moving partially over thearcuate member IOI (Fig. 1).

As trip shaft 262 is subsequently rotated in a clockwise direction totrip the mechanism to start the shutter drive, the first part of themovement draws arms 350 and 352 to the full line position of Figs. 16and 16a, surface 355 on arm 352 pulling the arcuate shutter operatinglug IOI around to the position illustrated in said figures, and causingthe auxiliary shutter to swing aside, as indicated. As the full lineposition of Fig. 16 is reached, the hook end 390 of an auxiliary shutterlatch 39I enters a notch 392 in the edge 353 of the arcuate lug IN. Theend surface 40I of latch hook 390 is concaved to conform to thecurvature of arcuate lug MI, and bears against the latter under theinfluence of a spring 402 pressing against arm 398 (Fig. 16) duringmovement of lug IM to latching" position. In the meantime, the camsurface 31I on arm 352 has been moving arm 352 laterally, and before thetime the dotted line position of Fig. 16 is reached, the cam shoulder at393 engaging roller 310 will have moved surface 353 clear of the lug MI.The auxiliary shutter is thus moved to open position,

and latched open by latch 39I, before arms 350 and 352 reach their finalposition (dotted lines in Fig. 16). That final position corresponds tothe position of trip shaft 262 in which release latch 212 is released tostart the shutter driving operation (dotted line positions in Fig. 12).

Auxiliary shutter latch 39I has a hub 396 rotatable on a shaft 391 setinto the housing structure (Figs. 1 and 16), and fast with hub 396 is anarm 399 carrying a roller 399 adapted to be engaged and moved to eITectrelease of latch 39I by a cam 400 secured to the underside of flange I94of gear I83 (see Figs. 6 and 16). Gear I83, it will be remembered, ispermanently timed with relation to the rotating shutters. The cam 400 isso located on gear flange I84 as to engage roller 399 and swing latch39I out of engagement with arcuate member I 0| just after the shutterexposure opening has closed, thereby releasing the auxiliary shutter toreturn to closed position under the influence of its spring I04 beforethe low speed shutter re-opens on the next revolution, and assuring thatthere will be no further exposures of the film as the mechanism coaststo a stop, even though there may be several additional coincidences ofhigh speed and low speed shutter openings at the exposure axis. The timeof releasing shutter latch 39I is indicated diagrammatically in Fig. 19;just after the closure of that high-speed shutter opening whichcoincides with the low-speed shutter opening. This gives the auxiliaryshutter a maximum period in which to swing closed before the next slowspeed shutter opening occurs. The auxiliary shutter is stopped in itsclosed position by its lug IOI striking the end of slot I02 in plate 41.

Preferably, a means is provided for assuring that the auxiliary shutterwill not rebound after it moves to closed position, and I here show forthis purpose a latching device consisting of a two armed latch H I (seeFigs. 4, 16a and 17) pivotally mounted at 4I2 between frame plate 41 anda supporting plate 4I3 mounted on a block 4I4 secured to plate 41. Plate3 is co-planar with frame plate 20 so that lug 354 can slide over it,and block 4I4 as well as plate 4I3 are accommoated by an aperture 5 inplate 20. One arm N1 of latch 4II carries an upwardly extending roller4I8 adapted to be engaged and moved against spring M8 by the advancingend 354 of arm 352, as that arm moves to the position of Fig. 1 at thebeginning of the operation of winding the driving spring. The other arm4I9 of the latch, which is fast with the first described arm, has a hook4I9a at the end adapted to engage in an aperture 420 in the arcuateshutter lug IM to lock the shutter in closed position. The auxiliaryshutter then remains locked in closed position until a subsequentrewinding operation is started. The advancing arm 352 then unlocks latchhook M9 and the auxiliary shutter is then moved open by the operationsthat release the driving spring to drive the rotating shutters. Afterbeing opened, the auxiliary shutter is again latched open; and this lastlatch is released in timed relation to the exposure operation of therotating shutters.

1, A shutter mechanism embodying an apertured shutter normallystationary but movable to cause its aperture to recurrently pass anexposure axis, shutter drive means adapted to accelerate the shutterinto movement and to drive said shutter to move its aperture a pluralityof times past said exposure axis, means to initiate driving of saidshutter by said shutter drive

